Artificial turf infill

Abstract

An artificial turf infill comprising an organic material including ground walnut shells having each organic particle completely coated with an anti-microbial agent. Water-retaining particles are added to the infill ranging between 0 and 60% of total weight of the mixture. Synthetic, ecologically-safe resilient granules preferably between approximately 20% and 25% by weight may be added to the infill to improve shock attenuation (lower G-max) properties of the infill mixture. The water-retaining particles and synthetic resilient granules within the infill are completely coated with the anti-microbial agent.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates generally to artificial turf playing surfaces for athletic games and, in particular, to an infill particulate material placed in and between artificial blades of grass.[0003]2. Description of the Prior Art[0004]Prior embodiments of artificial turf, commonly called “infilled turf” as disclosed in U.S. Pat. No. 4,337,283, issued Jan. 29, 1982 to Frederick T. Haas, Jr. and in U.S. Pat. No. 5,976,645 issued Nov. 2, 1997 to Daniel A. Daluise et al. represent a great improvement over the original short-pile artificial playing surfaces in that they reduce abrasiveness, increase shock attenuation, improve response to foot and ball actions, and have an improved appearance.[0005]These “infilled” turf systems incorporate an infill (particulate placed in and between the artificial grass blades), consisting of a mixture of rubber and sand or rubber, only. Because of its lower cost, the rubber used is almost ex...

AI Technical Summary

Benefits of technology

[0012]Accordingly, it is therefore an object of the present invention to provide an organic and / or inorganic artificial turf infill that is free of any synthetic chemicals, free of silica sand, environmentally-friendly, ecologically-safe, and non-supportive of microbial growth, and therefore resistant to decomposition.

[0016]It is a further object of this invention to provide an infill material with higher albedo and increased water absorption and retention capacity, thus increasing the capability to reduce surface temperature of the artificial turf through evaporative cooling.

[0017]It is yet another object of this invention to prevent microbial propagation in the infill matrix to not only prevent bacteria, fungi and mold growth but also to inhibit the decomposition of the organic materials actuated by microorganisms.

[0018]These and other objects are further accomplished by an artificial turf infill comprising organic particles and an anti-microbial agent applied to cover each of the organic particles to prevent decomposition of the organic particles. The organic particles preferably comprise ground walnut shells, and the organic particles may comprise one of a group consisting of ground coconut shells, ground pecan shells, ground peanut shells, ground corn cobs, and olive stones. The organic particles comprise a sieve-size in the range of 8 to 50. The infill comprises water retaining particles ranging between 0 and 60% of the total weight of said infill, each of the water retaining particles being covered with the anti-microbial agent. The water retaining particles comprise pozzolon, or may comprise one of a group consisting of vermiculite and calcined clay. The infill further comprises ecologically-sate, resilient synthetic granules, coated with the anti-microbial agent, to improve shock attenuating qualities of the infill when installed in the artificial turf.

[0019]The objectives are further accomplished for preparing the artificial turf infill by the process of grinding an organic hard material to form particles, and spraying an anti-microbial agent to completely coat each of the particles of the ground organic material thereby preventing decomposition of the ground organic particles. The step of grinding an organic hard material comprises the step of grinding walnut shells. The step of grinding an organic hard material to form particles comprises the step of grinding one of a group consisting of coconut shells, pecan shells, peanut shells, corn cobs, and olive stones. The process comprises the step of grinding the particles to a sieve-size in the range of 8 to 50. The process comprises the step of adding water retaining particles to the infill ranging between 0 and approximately 60% of the total weight of the infill prior to spraying the infill with the anti-microbial agent. The process further comprises the step of adding an ecologically-safe, resilient synthetic granules to the infill to improve shock attenuating properties of the infill prior to spraying the infill with the anti-microbial agent. The step of adding ecologically-safe, resilient synthetic granules to the infill comprises the step of adding a thermoplastic elastomer.

[0020]The objectives are further accomplished by the use of particles of a ground organic material, each of the particles coated with an anti-microbial agent to prevent decomposition of the particles, as infill material in an artificial turf system, wherein ground organic material comprises ground organic hard shells, such as walnut shells, or one of the group consisting of coconut shells, pecan shells, peanut shells, corn cobs, and olive stones. The use of particles of a ground organic material coated with an anti-microbial agent as infill material in the artificial turf system may further include water retaining particles coated with an anti-microbial agent, varying between 0 and 60% of the total weight of the infill. The water retaining particles comprise one of the group consisting of pozzolon, vermiculite and calcined clay, as infill material in the artificial turf system. The use of particles of a ground organic material coated with an anti-microbial agent as infill material in said artificial turf system may further include synthetic, ecologically-safe resilient granules coated with said anti-microbial agent preferably between approximately 20% and 25% by weight to improve shock activation properties.

Problems solved by technology

Rubber contains many problematic synthetic chemicals, such as polycyclic aromatic hydrocarbons (PAHs) and toxic heavy metals.

Others, such as lead, zinc and cadmium, also could be harmful to the environment, if introduced through run-off from infilled artificial turf fields.

Silica is also a known carcinogen and it is associated with silicosis and other respiratory harm.

Because these synthetic materials are not generally available in recycled form, their cost is a deterrent to their use and, because of cost, they are usually mixed with sand to achieve the full-depth of infill required, at a reasonable cost.

Such systems, therefore still suffer the concerns associated with silica sand, including the “Petri-dish effect” on microbe growth.

However, coconut shell and other natural organics carry their own set of concerns.

Since organic materials provide nutrients for microbes, they not only provide support for microbial growth, but also are susceptible to decomposition actuated by those same microbes.

However, this use of a vulcanized thermoplastic elastomer carries its own set of problems including high cost for the intended purpose, the perception of ecological risks associated with synthetic chemicals, and the necessity to mix with sand to reduce cost and achieve the proper “feel” and surface response.

However, this product carries the risk of ecologically harmful run-off from the surface applied thermoplastic polymers, a very high specific gravity and bulk-density, which greatly increases the weight of material required for a given depth of infill thus increasing total material cost and dramatically increasing freight costs, and the negative features of sand whereby it compacts over time thus inhibiting drainage and reducing shock attenuation.

However, this design carries the disadvantage of changing dimension (swelling) in water, which changes the surface configuration by increasing infill depth.

This results in a change in surface performance characteristics, as well as a change in surface response or “feel”.

In addition, the synthetic chemicals still carry the perceived ecological risks associated with exposure to synthetic chemicals.

However, this system is relatively high in cost for the intended use, requires the incorporation of “resilient particles” which are potentially environmentally and ecologically unsafe, and does not address the microbial growth problem.

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